Furnace stoker



March 21, 1939. A, WARD 2,151,574

FURNACE STOKER Filed May 16, 1936 2 Sheets-Sheet l f r H v. 39 a 1514 9g 27 I 'INV TOR. .Jrmma 4. i420 Marchzl, 1939. l WARD 2,151,574

FURNACE STOKER 2 Sheets-Sheet 2 Filed May 16, 1936 BY I ' ATTORNEY.

Patented Mar. 21, 1939 PATENT OFFICE FURNACE STOKE]!- Leonard A. Ward, Denver, Colo.', asslgnor to I). A. Ward, Inc. a corp ration of Colorado sive device which can be quickly applied to the usual household heating plant.

Another object of the invention is to provide a stoker structure in which the coal is fed from above and distributed over the incoming air so that the coal will be widely scattered into small particles. and suspended by the air so as to burn substantially in a state of suspension.

Further objects are to provide an efficient stoker which can utilize dust, "car-bottom and other inexpensive coals without forming a packed fuel bed and with a minimum of ash; and to. provide a feeding device which will effectively and uniformly feed flne coal without clogging and with but a minimum requirement of power.

, Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efllciency. These will become more apparent from the following description.

In the following detailed description of the invention reference is had to the accompanying drawings which form a part hereof. Like numerals refer to like parts in all views of the drawlugs and throughout the description.

In the drawings:.

stoker.

Fig. 2 is an outer face view thereof.

Fig. 3 is a detail plan view of the air distributor.

' Fig. 4 is a section through the distributor,

.35 taken on the line 4-4, Fig. 3.

t Fig. 5, is a right side-elevation of the improved stoker.

' Fig. 6 is a vertical section therethrough, taken on the line 6--6, Fig. 2.

' Fig. 7 is a detail section through the bottom of the coal hopper, taken on the line 1-1, Fig. 6. Fig. 8 isa detail face view of the coal discharge throat illustrating breaker teeth applied thereto. The word forward as used herein designates direction toward the furnace or burner.

The invention comprises a feed hopper l0 supported in a suitable supporting frame II. For convenience, the frame ll may be mounted upon caster wheels l2 which allow the stoker to be easily moved to any desired position.

The hopper I0 is provided with a partition plate l3 which divides the bottom thereofinto .a feed screw chamber l4 and a discharge chamber I5. A discharge throat 48 communicates be- 55 tween the chambers l4 and I5 through which Fig. 1 is a left side elevation of the improved 1936, Serial No. 80,117

the feed screw passes the coal. A discharge spout l8 leads from the discharge chamber IS. A shaft l6 extends horizontally through both chambers, and is provided with a feed screw I'l. On one extremity of the shaft I6 is a crank pin l9 which oscillates an agitating rod 20 which extends into the hopper l0 above the screw IT. The agitating arm. 20 prevents the coal from arching in the opening, andassures its downward movement to the feed screw i1.

The feed screw I! is intermittently rotated from an internally toothed ratchet wheel 2| which in the form shown is journaled on the right extremity of the shaft l6 and provided with an operating arm 39. The reciprocating motion of the ratchet wheel 2| is communicated to the shaft l6 by means of a spring actuated pawl 22. The ratchet wheel H is closed by means of a suitable cover plate 23, and it is preferred to mount an indicating hand 24 on the extremity of the shaft i6 beyond the cover 23 to indicate to the operator the movement of the shaft IS. The feed screw ll forces the coal over a lip 48 which prevents return flow thereof.

A reciprocating feed tube, which will be herein designated the jig tube" 25, is suspended below the hopper ill in the frame H. The jig tube 25 is supported at its outer extremity on an upwardly looped hanger 26 which is connected to the top of the tube 25 by a suitable bracket 21. At the inner side of the frame, the tube is suspended in a downwardly loopedhanger 28. An elongated feed sleeve 29 projects upwardly from the top of the tube 25 about the discharge spout 18 so that the jig tube 25 may reciprocate and still be at all times below the spout I8. Both extremities of the jig tube are open.

The reciprocation is imparted to the jig tube from an eccentric 30 mounted on a power shaft 3| immediately below the tube 25. The eccentric 30 is hingedly connected to the jig tube' by means or a very short eccentric strap 32 which is hinged to the tube at 33. Power is applied to the power shaft 3| from a suitable motor 34 by means of a belt and belt pulley 35 and 35, respectively. The'rotation of the power shaft acts to rapidly reciprocate the jig tube 25.

A reduction gear 31 is mounted on a suitable bearing and is driven from the power shaft 3| to operate a connecting rod 38 adjustably hinged to an arm 39 projecting from the ratchet wheel 2!, The connection to the arm 39 is through a sleeve 40 which can be adjusted along the arm a 39 and set in any desired position by means of a set screw 4| so as to vary the arc of movement of the ratchet wheel.

A blower 42 is mounted on the shaft of the motor 34 and supported in the frame H. The

blower discharges into an air pipe 43 through a flexible joint 44. The forward extremity of the air tube terminates in an air distributor 45 which is preferably positioned immediately below the outlet of the jig tube 25. The air distributor consists of a series of horseshoe shaped plates arranged below each other in cascading effect, as shown in Figs. 3 and 4, with the air exiting between the adjacent plates.

Operation The hopper I is filled with coal. This coal migrates to the feed screw I! which forces it at a predetermined rate into the feed chamber I5 and thence it falls into the jig tube 25. The peculiar vibration of the jig tube causes this coal to travel forwardly in a uniform continuous stream until it discharges from the forward extremity onto the air distributor 45.

From here, the coal cascades downwardly over the distributor plates where it meets the blast of air coming from the air pipe 43. This air forces the coal outwardly and upwardly into the firebox while it is burning. Thus, there is no pile of burning coal in the firebox. The combustion consists substantially of a blast of flame forced forwardly and upwardly from the distributor 45.

It has been found desirable to place breaking or cutting teeth, such as indicated at 41, Fig. 8, about the discharge throat 48. These serve to break up large lumps of coal before passing them to the chamber IS. A check-return ratchet 49 may be provided to prevent return movement of the shaft l6.

While a specific form of the improvement has been described and illustrated herein, it is deminating in said fumace; means for reciprocating said jig tube so as to cause coal to travel therealong; a blower; an air tube extending forwardly from said blower; and an air distributor carried by said air tube within said furnace below the discharge extremity of said jig tube, said distributor comprising: a series of horseshoe-like plates successively increasing in size so as to form a cascading arrangement, said plates being spaced apart so that the air from said air tube may discharge between them.

2. A coal stoker for a furnace comprising in combination, a coal hopper positioned adjacent said furnace; a discharge spout in the bottom of said hopper; a cylindrical jig tube having an open forward extremity terminating within said furnace, said jig tube being reciprocally suspended below said spout and having an opening for receiving the coal discharging from the latter; a feed screw conveying coal from said hopper to said spout; a ratchet wheel on said feed screw; a pawl for actuating said ratchet; an operating shaft extending transversely of said jig tube below the latter; an eccentric on said shaft for reciprocating said jig tube longitudinally; and a crank on said shaft for simultaneously recipro- 

